Don't get me wrong Rory is a good character and a good character for the show, but sadly I wouldn't have introduced Rory into the show at all. I would have actually introduced Sabrina the Teenage Witch. And have it that Sabrina was the child of Lucifer and Chloe for these reasons:

In the Chilling Adventures of Sabrina they have a Lucifer Morningstar of their own which was portrayed by Luke Cook. And in that had it that Sabrina was the first born child of Lucifer.

Plus Sabrina is also meant to be half witch and half human. And Lucifer is the devil and Chloe is human. It would have been perfect and made perfect sense for them to have Sabrina and make Sabrina even Canon in the Arrowverse like how the Chilling Adventures of Sabrina made Lucifer Morningstar Canon in the Archie comic world with having Lucifer be the father of Sabrina and also on top of that Sabrina is also meant to be a twin, it would have also been more better and far more interesting for the storyline with Sabrina in the show.

And the show could have had Dove Cameron as Sabrina, as Dove has experience with playing twins in a tv show, as she played the lead twins Liv and Maddy in the show Liv and Maddy.